Modem armament systems for military applications are increasingly more lethal and require more training for operators to be proficient in their use. Training operators can be accomplished by live fire exercises or simulated fire exercises. Wholly simulated fire exercises, however, often lack fidelity, whereas live fire exercises onto real target ranges require special and costly facilities and precautions. Moreover, live fire exercises onto many real target ranges have become more controversial. For example, use of Vieques Island and Hawaii as target ranges by the United States Navy has become politically unpopular, and the United States Federal Government has been compelled to withhold permission for all live fire exercises by the Navy at these sites.
Without an adequate substitute for wholly simulated fire exercises and by indefinitely closing target ranges to live fire exercises, the combat readiness of naval forces can be seriously impaired and a country's national defenses weakened. Thus, alternatives must be developed for naval preparedness. Appropriate to selecting alternative naval target ranges are concerns about using a populated island as a naval target range, the impact of such use on a regional ecosystem, other costs associated with such use, and locating an adequate environment for training personnel to operate naval weapon systems. Moreover, because the nature of naval fire exercises involves firing ordnance from very large caliber guns for long distances from a position in a body of water, many target range concepts are inadequate for use as naval target ranges.
E. Cardaillac et al., U.S. Pat. No. 6,296,486, Missile Firing Simulator with the Gunner Immersed in a Virtual Space, describes a simulator for firing weapons and includes a firing station and a missile weapon simulator. The simulator is a closed system primarily for shoulder held or tripod missile launchers for training users without using real projectiles or missiles. The firing station comprises a display device that can be a standard video screen or a large screen. The simulator does not accommodate a spotter because the simulator is designed for small-scale weapon systems. P. Wescott, U.S. Pat. No. 4,820,161, Training Aid, describes an apparatus for simulating artillery. It too is a closed system having a projection screen for displaying an image. Computer generated artillery shell bursts are overlaid on a photographic image of terrain by a video projector at locations commanded by a trainee observer.
A myriad of target range systems having sensors have been developed so that virtual targets can be displayed and fired upon from a given location. Examples are C. Sanctuary et al., U.S. Pat. No. 4,813,877, Remote Strafe Scoring System; V. Botarelli et al., U.S. Pat. No. 5,095,433, Target Reporting System; W. Zaenglein, Jr., U.S. Pat. No. 5,281,142, Shooting Simulating Process and Training Device; S. Koresawa et al., U.S. Pat. No. 5,551,876, Target Practice Apparatus; D. Downing, U.S. Pat. No. 5,577,733, Targeting System; and J. McAlpin et al., U.S. Pat. No. 5,676,548, Apparatus for Target Practice. Almost all of these describe apparatus for small arms or small weapon systems firing, and many of them are closed systems. Consequently, they implement target ranges by projections onto plates, sheets, and screens. Sensors are used to provide computer systems with data to locate impact points, which sensors span a variety of types, from light panels to acoustic sensors to pressure sensitive sensors. Like the simulators cited above, they do not accommodate a spotter.
One “hardware-in-the-loop” simulator is described by G. Waldman et al., U.S. Pat. No. 5,224,860, Hardware in the Loop Tow Missile System Simulator. The system is specific to TOW missile systems, wherein a simulation module creates a battlefield environment including at least one moveable target. Another system, described in R. Adams, U.S. Pat. No. 5,415,548, System and Method for Simulating Targets for Testing Missiles and Other Target Driven Devices, has both a background memory and a target memory and overlaps selected frames from the target memory onto the selected background to create a virtual target. This information is input into a missile or other target driven device to indicate the presence and position of the target and to test the responsiveness of the device.
The United States Navy has experimented with solutions of its own. One solution uses a flat view of a simulated island on weapon system displays as a virtual target range to support live fire exercises. This kind of simulation has been used at the United States Naval Pacific Missile Range Facility at Barking Sands in Kauai, Hawaii. This facility uses an array of fixed survey buoys anchored at pre-determined offshore locations. A graphic of an island (topographic map) is then “overlaid” onto the buoys' global coordinates on a map or display, and naval weapon systems are directed to fire at particular locations on the virtual island. Sensor on the buoys record the impacts of rounds on the water. The sensor data for each buoy includes a time-stamp and location of the respective buoy, and is communicated back to a central processing station where the data is used to compute the trajectory of a round and the impact point of the round. From this information, a virtual impact point with respect to the previously implemented, flat virtual target range is calculated and overlain onto the target range. Another example is the Potomac River Test Range of the United States Naval Surface Weapon Center Dahlgren Division. This facility superimposes a flat image of the north end of San Clemente Island over an impact area defined on the Potomac River using an IMPASS buoy system where by each buoy is free-floating and equipped with a hydro-phonic sensor and global positioning system.
The virtual target range systems described above use a set of buoys and a computer system to sense, analyze, and calculate impact points of naval weapon system fire exercises. Sensors on the fixed buoys record the impact points of live fire exercises on the water, from which the virtual impact points on virtual target ranges are calculated. Installing these buoys, however, is costly and they require regular maintenance. Also, anchoring buoys in deep-sea locations requires special technical training and safety precautions. Free floating buoys can be used in the open ocean, but deploying and recovering these kinds of buoys also has problems, such as requiring additional manpower and managing the associated risks and time delays.
Moreover, most current virtual target range systems are used primarily for testing delivery accuracy of weapon systems, but not for training spotters or survey teams. Current systems are based on the assumption that spotters will need tele-presence. Consequently, spotters still use visual contact to acquire a surface water impact on a range. They cannot make adjustments to a fire exercise since they only see surface water and not a virtual target range. In addition, fixed buoys have to be pre-installed at specific locations. Ships thus may have to sail thousands of miles to those locations for training. Finally, and most importantly, the systems discussed above do not provide the flexibility of anywhere-anytime simulation and training.